SLIME-HEADS. 353 



side of Tropical America ; our illustration showing a member of the former genus 

 (P. schomburgki). These fishes are characterised by the absence of a lateral line, 

 and the great number of 

 spines in both the dorsal 

 and anal fins. The thoracic 

 pelvic fins have one spine 

 and five rays, and the teeth 

 are feeble. These fishes are 

 all of very small size, and 

 are stated to feed ex- 

 clusively upon insects. 



The single 



Teuthis. 



generic repre- 

 sentative of the Teuthididce, schomburgk's many-spine (f nat. size), 

 of which a species {Teuthis 



striolata) is shown in the illustration on p. 354, is characterised by the tooth- 

 less palate, and the presence of a series of narrow serrated incisor teeth in the 

 front of each jaw. The scales on the oblong and compressed body are very 

 small, and there is a continuous lateral line. In the single dorsal fin the spinous 

 considerably exceeds the soft portion in length ; the anal has seven spines ; and 

 the thoracically-placed pelvic fins have an outer and inner spine, between which 

 are three rays. These fishes have a large air-bladder, forked at both extremities ; 

 and they also display several peculiarities in the structure of the skeleton ; the 

 abdomen being surrounded by a complete ring of bones, owing to the backward 

 prolongation of certain elements of the pectoral arch, and the unusual develop- 

 ment of the pelvis. A considerable number of species have been described from 

 the Indo- Pacific, where their eastward range stops about the longitude of the 

 Sandwich Islands. The largest of them is not more than 15 inches in length, and 

 all are vegetable-feeders. In the figured species, which is from the New Hebrides, 

 the general colour is brownish red, marked with narrow vermiculated blue lines ; 

 the spines of the fins also bearing white spots. 



The Berycoids or Slime-Heads, — Family BerychiDjE. 



With the slime-heads we come to a family distinguished from the whole of 

 the preceding, and forming a group by itself characterised by the presence on 

 the head of large mucous-bearing cavities, covered with a thin skin, and by the 

 thoracically-situated pelvic fins having one spine and five rays (save in Monocentris, 

 where the latter are reduced to two). The compressed body may be either oblong 

 or deep in form, but is always short ; and the scales, which are rarely wanting, 

 are of the ctenoid type. Lateral in position, the eyes are almost always large in 

 size; the lateral cleft of the mouth slopes obliquely upwards; the teeth in the 

 jaws are villiform ; teeth are in most cases developed on the palatines ; the bones 

 of the gill-cover are more or less fully armed ; and there are nearly always eight 

 branchiostegal rays, although these are sometimes reduced to four. There are no 

 scales on the head, and false gills are present. The slime-heads, which comprise 



vol. v. — 23 



